Acne is a skin condition that occurs when your hair follicles become plugged with oil and dead skin cells. Acne usually appears on your face, neck, chest, back and shoulders. Effective treatments are available, but acne can be persistent. The pimples and bumps heal slowly, and when one begins to go away, others seem to crop up.

Acne is most common among teenagers, with a reported prevalence of 70 to 87 percent. Increasingly, younger children are getting acne as well.

Depending on its severity, acne can cause emotional distress and scar the skin. The earlier you start treatment, the lower your risk of lasting physical and emotional damage.

Acne signs and symptoms vary depending on the severity of your condition:

Whiteheads (closed plugged pores)

Blackheads (open plugged pores — the oil turns brown when it is exposed to air)

When to see a doctor

If home care remedies don't work to clear up your acne, see your primary care doctor. He or she can prescribe stronger medications. If acne persists or is severe, you may want to seek medical treatment from a doctor who specializes in the skin (dermatologist).

The Food and Drug Administration warns that some popular nonprescription acne lotions, cleansers and other skin products can cause a serious reaction. This type of reaction is quite rare, so don't confuse it with the redness, irritation or itchiness where you've applied medications or products.

Seek emergency medical help if after using a nonprescription skin product you experience:

Faintness

Difficulty breathing

Swelling of the eyes, face, lips or tongue

Tightness of the throat

Four main factors cause acne:

Oil production

Dead skin cells

Clogged pores

Bacteria

Acne typically appears on your face, neck, chest, back and shoulders. These areas of skin have the most oil (sebaceous) glands. Acne occurs when hair follicles become plugged with oil and dead skin cells.

Hair follicles are connected to oil glands. These glands secrete an oily substance (sebum) to lubricate your hair and skin. Sebum normally travels along the hair shafts and through the openings of the hair follicles onto the surface of your skin.

When your body produces an excess amount of sebum and dead skin cells, the two can build up in the hair follicles. They form a soft plug, creating an environment where bacteria can thrive. If the clogged pore becomes infected with bacteria, inflammation results.

The plugged pore may cause the follicle wall to bulge and produce a whitehead. Or the plug may be open to the surface and may darken, causing a blackhead. A blackhead may look like dirt stuck in pores. But actually the pore is congested with bacteria and oil, which turns brown when it's exposed to the air.

Pimples are raised red spots with a white center that develop when blocked hair follicles become inflamed or infected. Blockages and inflammation that develop deep inside hair follicles produce cyst-like lumps beneath the surface of your skin. Other pores in your skin, which are the openings of the sweat glands, aren't usually involved in acne.

Factors that may worsen acne

These factors can trigger or aggravate an existing case of acne:

Hormones. Androgens are hormones that increase in boys and girls during puberty and cause the sebaceous glands to enlarge and make more sebum. Hormonal changes related to pregnancy and the use of oral contraceptives also can affect sebum production. And low amounts of androgens circulate in the blood of women and can worsen acne.

Diet. Studies indicate that certain dietary factors, including dairy products and carbohydrate-rich foods — such as bread, bagels and chips — may trigger acne. Chocolate has long been suspected of making acne worse. A recent study of 14 men with acne showed that eating chocolate was related to an increase in acne. Further study is needed to examine why this happens or whether acne patients need to follow specific dietary restrictions.

Stress. Stress can make acne worse.

Acne myths

These factors have little effect on acne:

Greasy foods. Eating greasy food has little to no effect on acne. Though working in a greasy area, such as a kitchen with fry vats, does because the oil can stick to the skin and block the hair follicles. This further irritates the skin or promotes acne.

Dirty skin. Acne isn't caused by dirt. In fact, scrubbing the skin too hard or cleansing with harsh soaps or chemicals irritates the skin and can make acne worse. Though it does help to gently remove oil, dead skin and other substances.

Hormonal changes. Such changes are common in teenagers, women and girls, and people using certain medications, including those containing corticosteroids, androgens or lithium.

Family history. Genetics plays a role in acne. If both parents had acne, you're likely to develop it, too.

Greasy or oily substances. You may develop acne where your skin comes into contact with oily lotions and creams or with grease in a work area, such as a kitchen with fry vats.

Friction or pressure on your skin. This can be caused by items such as telephones, cellphones, helmets, tight collars and backpacks.

Stress. This doesn't cause acne, but if you have acne already, stress may make it worse.

If you have acne that's not responding to self-care and over-the-counter treatments, make an appointment with your doctor. Early, effective treatment of acne reduces the risk of scarring and of lasting damage to your self-esteem. After an initial examination, your doctor may refer you to a specialist in the diagnosis and treatment of skin conditions (dermatologist).

Here's some information to help you get ready for your appointment.

What you can do

List your key medical information, such as other conditions with which you've been diagnosed and any prescription or over-the-counter products you're using, including vitamins and supplements.

List key personal information, including any major stresses or recent life changes.

List questions to ask your doctor. Creating your list of questions in advance can help you make the most of your time with your doctor.

Below are some basic questions to ask your doctor about acne. If any additional questions occur to you during your visit, don't hesitate to ask.

What treatment approach do you recommend for me?

If the first treatment doesn't work, what will you recommend next?

What are the possible side effects of the medications you're prescribing?

How long can I safely use the medications you're prescribing?

How soon after beginning treatment should my symptoms start to improve?

When will you see me again to evaluate whether my treatment is working?

Is it safe to stop my medications if they don't seem to be working?

What self-care steps might improve my symptoms?

Do you recommend any changes to my diet?

Do you recommend any changes to the over-the-counter products I'm using on my skin, including soaps, lotions, sunscreens and cosmetics?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to talk about in-depth. Your doctor may ask:

When did you first develop this problem?

Does anything in particular seem to trigger an acne flare, such as stress or — in girls and women — your menstrual cycle?

What medications are you taking, including over-the-counter and prescription drugs as well as vitamins and supplements?

In girls and women: Do you use oral contraceptives?

In girls and women: Do you have regular menstrual periods?

In girls and women: Are you pregnant, or do you plan to become pregnant soon?

What types of soaps, lotions, sunscreens, hair products or cosmetics do you use?

How is acne affecting your self-esteem and your confidence in social situations?

Do you have a family history of acne?

What treatments and self-care steps have you tried so far? Have any been effective?

If over-the-counter (nonprescription) products haven't cleared up your acne, your doctor can prescribe stronger medications or other therapies. A dermatologist can help you:

Control your acne

Avoid scarring or other damage to your skin

Make scars less noticeable

Acne medications work by reducing oil production, speeding up skin cell turnover, fighting bacterial infection or reducing inflammation — which helps prevent scarring. With most prescription acne drugs, you may not see results for four to eight weeks, and your skin may get worse before it gets better. It can take many months or years for your acne to clear up completely.

The drug your doctor recommends depends on the type and severity of your acne. It might be something you apply to your skin (topical medication) or take by mouth (oral medication). Often, drugs are used in combination. Pregnant women will not be able to use oral prescription medications for acne.

Talk with your doctor about the risks and benefits of medications and other treatments you are considering.

Topical medications

These products work best when applied to clean, dry skin about 15 minutes after washing. You may not see the benefit of this treatment for a few weeks. And you may notice skin irritation at first, such as redness, dryness and peeling.

Your doctor may recommend steps to minimize these side effects, including using a gradually increased dose, washing off the medication after a short application or switching to another medication.

The most common topical prescription medications for acne are:

Retinoids. These come as creams, gels and lotions. Retinoid drugs are derived from vitamin A and include tretinoin (Avita, Retin-A, others), adapalene (Differin) and tazarotene (Tazorac, Avage). You apply this medication in the evening, beginning with three times a week, then daily as your skin becomes used to it. It works by preventing plugging of the hair follicles.

Antibiotics. These work by killing excess skin bacteria and reducing redness. For the first few months of treatment, you may use both a retinoid and an antibiotic, with the antibiotic applied in the morning and the retinoid in the evening. The antibiotics are often combined with benzoyl peroxide to reduce the likelihood of developing antibiotic resistance. Examples include clindamycin with benzoyl peroxide (Benzaclin, Duac, Acanya) and erythromycin with benzoyl peroxide (Benzamycin).

Dapsone (Aczone). This gel is most effective when combined with a topical retinoid. Skin side effects include redness and dryness.

Oral medications

Antibiotics. For moderate to severe acne, you may need oral antibiotics to reduce bacteria and fight inflammation. Choices for treating acne include tetracyclines, such as minocycline and doxycycline.

Your doctor likely will recommend tapering off these medications as soon as your symptoms begin to improve or as soon as it becomes clear the drugs aren't helping — usually, within three to four months. Tapering helps prevent antibiotic resistance by minimizing undue exposure to these medications over a long time.

You will likely use topical medications and oral antibiotics together. Studies have found that using topical benzoyl peroxide along with oral antibiotics may reduce the risk of developing antibiotic resistance.

Antibiotics may cause side effects, such as an upset stomach and dizziness. These drugs also increase your skin's sun sensitivity. They can cause discoloration of developing permanent teeth and reduced bone growth in children born to women who took tetracyclines while pregnant.

The most common side effects of these drugs are headache, breast tenderness, nausea, weight gain and breakthrough bleeding. A serious potential complication is a slightly increased risk of blood clots.

Anti-androgen agent. The drug spironolactone (Aldactone) may be considered for women and adolescent girls if oral antibiotics aren't helping. It works by blocking the effect of androgen hormones on the sebaceous glands. Possible side effects include breast tenderness, painful periods and the retention of potassium.

Isotretinoin. This medicine is reserved for people with the most severe acne. Isotretinoin (Amnesteem, Claravis, Sotret) is a powerful drug for people whose acne doesn't respond to other treatments.

Oral isotretinoin is very effective. But because of its potential side effects, doctors need to closely monitor anyone they treat with this drug. The most serious potential side effects include ulcerative colitis, an increased risk of depression and suicide, and severe birth defects.

In fact, isotretinoin carries such serious risk of side effects that women of reproductive age must participate in a Food and Drug Administration-approved monitoring program to receive a prescription for the drug.

Therapies

These therapies may be suggested in select cases, either alone or in combination with medications.

Light therapy. A variety of light-based therapies have been tried with success. But further study is needed to determine the ideal method, light source and dose. Light therapy targets the bacteria that cause acne inflammation. Some types of light therapy are done in a doctor's office. Blue-light therapy can be done at home with a hand-held device.

Possible side effects of light therapy include pain, temporary redness and sensitivity to sunlight.

Chemical peel. This procedure uses repeated applications of a chemical solution, such as salicylic acid. It is most effective when combined with other acne treatments, except oral retinoids. Chemical peels aren't recommended for people taking oral retinoids because together these treatments can significantly irritate the skin.

Chemicals peels may cause temporary, severe redness, scaling and blistering, and long-term discoloration of the skin.

Extraction of whiteheads and blackheads. Your dermatologist uses special tools to gently remove whiteheads and blackheads (comedos) that haven't cleared up with topical medications. This technique may cause scarring.

Steroid injection. Nodular and cystic lesions can be treated by injecting a steroid drug directly into them. This improves their appearance without the need for extraction. The side effects of this technique include thinning of the skin, lighter skin and the appearance of small blood vessels on the treated area.

Treating acne scars

Procedures used to diminish scars left by acne include the following:

Soft tissue fillers. Injecting soft tissue fillers, such as collagen or fat, under the skin and into indented scars can fill out or stretch the skin. This makes the scars less noticeable. Results are temporary, so you would need to repeat the injections periodically. Side effects include temporary swelling, redness and bruising.

Chemical peels. High-potency acid is applied to your skin to remove the top layer and minimize deeper scars.

Dermabrasion. This procedure is usually reserved for more severe scarring. It involves sanding (planing) the surface layer of skin with a rotating brush. This helps blend acne scars into the surrounding skin.

Laser resurfacing. This is a skin resurfacing procedure that uses a laser to improve the appearance of your skin.

Light therapy. Certain lasers, pulsed light sources and radiofrequency devices that don't injure the epidermis can be used to treat scars. These treatments heat the dermis and cause new skin to form. After several treatments, acne scars may appear less noticeable. This treatment has shorter recovery times than some other methods. But you may need to repeat the procedure more often and results are subtle.

Skin surgery. Using a minor procedure called punch excision, your doctor cuts out individual acne scars and repairs the hole at the scar site with stitches or a skin graft.

Treating children

Most studies of acne drugs have involved people 12 years of age or older. Increasingly, younger children are getting acne as well. In one study of 365 girls ages 9 to 10, 78 percent of them had acne lesions. If your child has acne, you may want to consult a pediatric dermatologist. Ask about drugs to avoid in children, appropriate doses, drug interactions, side effects, and how treatment may affect a child's growth and development.

Treatment of children with acne is often complicated by their family situation. For example, if a child moves between two homes due to divorced parents, it may help to use two sets of medications, one in each home.

You can try to avoid or control mild acne with nonprescription products, good basic skin care and other self-care techniques:

Wash problem areas with a gentle cleanser. Twice a day, use your hands to wash your face with a mild soap and warm water. If you tend to develop acne around your hairline, shampoo your hair every day.

Avoid certain products, such as facial scrubs, astringents and masks, because they tend to irritate skin, which can worsen acne. Excessive washing and scrubbing also can irritate skin. And be gentle while shaving affected skin.

Try over-the-counter acne products to dry excess oil and promote peeling. Look for products containing benzoyl peroxide as the active ingredient. You might also try products containing sulfur, resorcinol or salicylic acid. Nonprescription acne medications may cause initial side effects — such as redness, dryness and scaling — that often improve after the first month of using them.

The Food and Drug Administration warns that some popular nonprescription acne lotions, cleansers and other skin products can cause a rare but serious reaction.

Avoid irritants. You may want to avoid oily or greasy cosmetics, sunscreens, hairstyling products or acne concealers. Use products labeled water-based or noncomedogenic, which means they are less likely to cause acne.

Use an oil-free moisturizer with sunscreen. For some people, the sun worsens acne. And some acne medications make you more susceptible to the sun's rays. Check with your doctor to see if your medication is one of these. If it is, stay out of the sun as much as possible. Regularly use a nonoily (noncomedogenic) moisturizer that includes a sunscreen.

Watch what touches your skin. Keep your hair clean and off your face. Also avoid resting your hands or objects, such as telephone receivers, on your face. Tight clothing or hats also can pose a problem, especially if you're sweating. Sweat and oils can contribute to acne.

Don't pick or squeeze blemishes. Doing so can cause infection or scarring.

Some studies suggest that using the following supplements may help treat acne. More research is needed to establish the potential effectiveness and long-term safety of these and other natural acne treatments, traditional Chinese medicine, and ayurvedic herbs.

Talk with your doctor about the pros and cons of specific treatments before you try them.

Tea tree oil. Gels containing 5 percent tea tree oil may be as effective as are lotions containing 5 percent benzoyl peroxide, although tea tree oil might work more slowly. Possible side effects include contact dermatitis and, if you have rosacea, a worsening of those symptoms. One study reported that a young boy experienced breast development after using a combination lavender and tea tree oil hair product. Tea tree oil should be used only topically.

Alpha hydroxy acid. This natural acid is found in citrus fruit and other foods. When applied to your skin, it helps remove dead skin cells and unclog pores. It may also improve the appearance of acne scars. Side effects include increased sensitivity to the sun, redness, mild stinging and skin irritation.

Azelaic acid. This natural acid is found in whole-grain cereals and animal products. It has antibacterial properties. A 20 percent azelaic acid cream seems to be as effective as many other conventional acne treatments when used twice a day for at least four weeks. It is even more effective when used in combination with erythromycin. Prescription azelaic acid (Azelex, Finacea) is an option during pregnancy and while breastfeeding.

Green tea extract. A lotion of 2 percent green tea extract helped reduce acne in two studies of adolescents and young adults with mild to moderate acne.

Aloe vera. A 50 percent aloe vera gel was combined with a conventional acne drug (tretinoin) and tested for 8 weeks on 60 people with moderate acne. The combination approach was significantly more effective than tretinoin alone.

Brewer's yeast. A specific strain of brewer's yeast, called CBS 5926, seems to help decrease acne. Brewer's yeast is the only item in this list that's taken orally. It may cause flatulence.

Acne and the scars it can cause may affect your social relationships and self-esteem. Sometimes it can help to talk with your family, a support group or a counselor.

Once your acne improves, you may need to continue your acne medication or other treatment to prevent new breakouts. You might need to use a topical medication on acne-prone areas, continue taking oral contraceptives or attend ongoing light therapy sessions. Talk to your doctor about how you can keep your skin clear.

Remove makeup before going to bed. Going to sleep with cosmetics on your skin can clog your pores. Also, it's a good idea to throw out old makeup and regularly clean your cosmetic brushes and applicators with soapy water.

Caperton C, et al. Double-blind, placebo-controlled study assessing the effect of chocolate consumption in subjects with a history of acne vulgaris. The Journal of Clinical and Aesthetic Dermatology. 2014;7:19

Han Song B, et al. Photodynamic therapy using chlorophyll-a in the treatment of acne vulgaris: A randomized, single-blind, split-face study. Journal of the American Academy of Dermatology. In press. Accessed June 24, 2014.

Wheeland R, et al. Safety and effectiveness of a handheld blue light device for self-treatment of mild to moderate acne. Journal of the American Academy of Dermatology. 2012;66(suppl):AB18.

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